Its best to completely flush, but not totally necessary if you use the correct oil. The new oil will flow through the system, the old oil (not soluble in the R134) will tend to collect in the crankcase of the compressor, where it is needed.

I did the 220D the other years, still works fine as far as I can tell, since I haven't run it for a while.

Ditto for the Volvo, but I also had to replace the orifice tube in that, and probably will need a new compressor (lots of gray crap in there, often the "gray death compressor syndrome).


Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!